BossCat's Push Trailer

[BossCat]

I got a phone call from my mate telling me my motor had arrived, I nipped of to collect it

36V 500W Electric Motor Electric Bike, Scooter 2500RPM

After unpacking the motor my mate tested it on his battery booster (for jump starting cars), the motor span up, he then tested it on another booster, and finnally we tested it on a cordless drill batt. All three tests we suscessfull.
When I got home I further tested it on a Kinetic 12V 7ah/20hr battery I have, it was then a thought occured to me - Which way does the motor spin?

In this photo with the motor sitting on top of my trailer (just for demonstration purpose) the motor spins anticlock wise..

where as the trailer wheel below needs to turn clock wise to drive.

The only way I can now think of mounting the motor would be like this.....

With the motor just in front of the wheel, sticking far enough out to catch the chain line of the cog when I swap the trailer wheels around - so that the drive cog is on the outside.
The only other way I can think? is keep all as is and reverse the polarity + - on the motor so it spins clock wise?
QUESTION
Would reversing the polarity + - harm the motor?

Its the only thing I can think of when I see pictures like this...

Regards
Tom

 

[corgi1]

I would think the motor is made to run most powerful the right direction,and weaker reversed,,,,You may need to rearange the components in the trailer and put the motor on the same side as the one pictured above,and the pic above with the motor mounted on the ground would greatly limit the distance you could travel lol............Just my opinion

 

[rustymullet]

Smaller electric motors such as electric rc you can easily reverse motor to make it a pusher or puller type motor. I would think the same applies to a larger scale motor . It's all in the physics. rusty mullet

 

[BossCat]

I would think the motor is made to run most powerful the right direction,and weaker reversed,,,,You may need to rearange the components in the trailer and put the motor on the same side as the one pictured above,and the pic above with the motor mounted on the ground would greatly limit the distance you could travel lol............Just my opinion

I think you missed the point. In the picture below....
Bike - Trailer wheels and motor all running in an Aticlockwise direction as you look at picture.

If I set my trailer and motor up like that I would have my Bike - Trailer wheels running anticlock and my motor running clock wise, unless I reverse the polartity on my battery.

Thats why I was asking if any harm would be done or loss of power to the motor if I reversed the polarity.

To keep the polartity I would need to set my trailer up like Decon's PAT Trailer, with the motor on the other side of the trailer.....

Regards
Tom

 

[deacon]

The only time I ever had a problem running a motor backwards was when it had a clutch attached to the end of the shaft. Otherwise I have run them in either direction with no problem at all. I really like the attachment to the bike to make the hook up. It looks to be a hundred times stronger than mine was.

That little pusher of mine ran really nice, it would have been even better with 36v. Too bad I didn't keep it so that I could run it till it killed me lol.

I like your design for the trailer. I have gone with the classic support on each side of the wheel. the trailer is ugly as **** but it is stronger than a bull.

 

[zabac70]

Changing polarity won't hurt motor , if it is a brushless motor (DC). Performance would be the same either way. Some of these motors (don't know if it is the case with yours) have diode incorporated within them , but in that case if you switch "+" and "-" it just wouldn't work - no damage will occur. In that case something should be done with controller to reverse direction of rotation.

 

[deacon]

Be sure you switch the motor wires not the battery ones. I know you knew that but what the heck somebody might not.

 

[BossCat]

Be sure you switch the motor wires not the battery ones. I know you knew that but what the heck somebody might not.

No I never knew that, plus I've no idea what you mean?

Motor has RED and BLACK wires coming from it. I hook up to a batt with RED wire to Pos and BLACK wire to Neg, motor runs clockwise. If I reverse the wires, RED wire to Neg and BLACK wire to Pos the motor runs anticlock wise like I want.

Anyway here's what's been done so far.
I stripped down a bike wheel and seperated all the cogs. I got my mate to weld a plate onto the cog then drill and file a hole so that the plate slips over the motor spindal. I then stripped the large cog of an old bike pedal and got my mate to weld the cog to a wheel. Wheel hooked everything up to a trailer and tested it. It ran ok if a little off center.

deacon
I like your design for the trailer. I have gone with the classic support on each side of the wheel. the trailer is ugly as **** but it is stronger than a bull.

Sadly the trailer pictured (i used for refrence) is not mine, I only wish it was.

The build for this trailer is here - Endless-sphere.com • View topic - Ross' bike pusher (trailer) project...

This is MY trailer....

This was the trailer before I changed the tow arm, I done this as I dont think that the little towball I have on the tow arm would hold up to the stress put on it by any motor.

I took the towarm off my monowheel trailer and attached it to my motor trailer as I thought this would be a stronger setup. After a test ride (no motor on, need to get batts) I found the bike unsteady and pulled to one side? I think this maybe because my mate welded the towarm a bit squint? Im going to try another steering stem under the angled plate to give the trailer rotation to see if it helps.

Regards
Tom

 

[corgi1]

==================================================================
I took the towarm off my monowheel trailer and attached it to my motor trailer as I thought this would be a stronger setup. After a test ride (no motor on, need to get batts) I found the bike unsteady and pulled to one side?
==================================================================
I am looking at the pic and asking did the bike pull left?,,,if it did the motor chain on this side may cause drag too the left.
I think the drag would be less if you could make the pivit for the hitch adjustable ,and could move toward the motor side of the trailer,,this would put the drag more directly behind the bike tire.

 

[corgi1]

Another Question? ,,does that hitch mount allow the bike to lean as you corner with out hindering free leaning of the bike?,,,

 

[BossCat]

Another Question? ,,does that hitch mount allow the bike to lean as you corner with out hindering free leaning of the bike?,,,

No, not at the moment hence my last line...
Im going to try another steering stem under the angled plate to give the trailer rotation to see if it helps.

Im going to try the stem as at the moment the trailer pulls like im riding a trike, wheels come off the ground when cornering.

Regards
Tom

 

[deacon]

To keep my pusher in line with the bike, so that it didn't push me from a funky angle, I had to attach it to both sides of the bike. It made right turns from a dead stop drag the push wheel to the side, otherise it did just fine.

 

[zabac70]

No, not at the moment hence my last line...
Im going to try another steering stem under the angled plate to give the trailer rotation to see if it helps.

Im going to try the stem as at the moment the trailer pulls like im riding a trike, wheels come off the ground when cornering.

Regards
Tom

I'm not sure if it is a good idea. The propulsion wheels should be kept in touch with the surface of the road as much time as possible. Imagine a bump on the road while you make a corner - mass of the trailer can easily put you in the air (off the bike). You should be able to lean the bike , while trailer is on the road with both wheels. Keep in mind that rear wheel of the bike is actually steering wheel for the trailer. As I see it, there is a few problems with this setup. First , when making a corner wheels should be turning at different speeds (like in a car - differential is taking care of that) - the problem occurs when you want to take turn on the opposite side of the driving wheel - the inner wheel should be turning slower then the outer one and I don't think that is possible because of the free wheel (if you use one on your setup) or live axle. Trailer wants to go straight , while you want to take a turn - and you get a conflict of interests
Second , hitching arm amplifies forces (it's a lever) of swiveling trailer , which can not be controlled easily at any reasonable speed (something like a car pulling caravan trailer on a road). Short arm is better (the trailer axle should be as close as possible to rear wheel axle) and rear suspension might help with it too, or some kind of suspension on the hitching point.
Third , if you address "differential" problem , you should be sure that everything is dead straight (all wheels longitudinal axes must be parallel).
One wheel pusher trailer is so much easy-er to handle and match with bike(there are some considerations with it too).
P.S. Sorry , I've just saw the picture of your trailer(I thought that the first picture is your trailer) - you have two separate wheels. In your case, you have the offset propulsion , which will be hard to make to behave itself. My best advice is to reconfigure the trailer.

 

[BossCat]

I have just added another fork stem on my angled plate (still have to cut and bolt a few bits) this gives my trailer the rotation needed. I have done a quick test ride and all is well so far. Famous last words

ROTATION...

As you can see from the pictures the trailer now has rotation in all directions. The added purple stem allows the bike to tilt when cornering and the trailer stay put with both wheels on the ground.

Further testing is needed to see if this all holds up.

Regards
Tom

 

[zabac70]

Did you test only empty trailer ?

 

[BossCat]

Did you test only empty trailer ?

Yes, I have only tested the emtpy trailer, barring the weight of the motor.

Today I plan to move the motor under the trailer, this will allow me to put my thin plywood floor back on. I'll also rig up some batts and try a test run. I probably dont have the right batterys? Here's what batts I have.

2 Kinetic 12V 7AH/20HR.
1 Deep Cycle Battery 12V 93AH. This is a very heavy batt (66LB) I got for a solar power project. I dont plan on using it on the trailer barring for testing.
1 Yuasa motor bike battery I got from my mate. This is 12V amps unknown.

I'll try wiring the 2 kinetic and the yuasa battery in series to give me the 36V I need to power my 36V 500W motor.

I'll report back later with the results of my tests.

Regards
Tom

 

[deacon]

keep us posted. Sounds like you have it all ready to go. I just realized by looking at the picture of my old pusher that I ran it at 24 volts and it was a very efficient propulsion system. I bet at thirty six it would have hummed. Now I am really curious as to how you do with yours.

 

[BossCat]

Rain stopped play

When I posted earlier today the sun was splitting the trees. I moved the motor under the trailer and bolted down the floor, I then began wiring up the batterys. While I was in the middle of wiring up the batts a downpour started
Once the rain let up a bit I jacked the trailer up on bricks and tested the motor. It span up great. I then tried a test run - nothing!
I tried the bike and trailer without me sitting on it and still nothing! The motor kicks in but it just wont turn the wheels? I may need bigger/better battrerys? I cant see hooking up the big deep cycle battery doing any good as the weight would be a killer.

Looks like its back to the drawing board! This rain aint helping any with my testing, I think I'll have to hold off until better weather.

Regards
Tom

 

[zabac70]

You should use multimeter on the batteries to see how many amps motor eating and check on voltage drop during the action. Maybe the batteries have died and when you put some load on them they just short out (hence no movement on the trailer). You can put any battery (even 24 V setup of any amount of Amp h will do for a purpose of testing the system).

 

[deacon]

let me see your motor turns with no weight in the trailer. If that is the case then your wiring is fine. Will it turn the wheel if the trailers is jacked up. if so then your drive system is right. If those two happen then it has to be your batteries unable to provide enough amps to move the bike and rider. You might want to double check your battery connections. Sometimes mine work loose and they will provide some current but not full current.

As was mentioned it might be old batteries that discharge instantly under load. What size controller are you running. If your total volts from the battery is too low the controller will shut down completely. I personally would jack the trailer up and see if the wheel will turn when I give it throttle. If so I would check my connections. If they are good i would change out one battery at a time until the bike moves.

If the wheel won't turn check the voltage at every junction. At the connection to the controller. At the motor connection with the throttle movement it should go up and down there. You probably know all this so sorry if sound like a jerk. I have had problems at every point in the circuit at one time or another, so I mention it in passing.